My puppy will be 14 weeks old tomorrow and she is the same way! Happy to see people, approaches with a wagging, low tail, and sits politely for petting. She's been like this since we got her at 9 weeks. I too was concerned that perhaps I missed the signs of a shy puppy when picking her and so I decided against waiting to socialize. After her first shots, I took her everywhere with me. To me personally, it was a MUCH greater risk to have a fear aggressive dog vs. any illness. A risk I had to take. At 9 weeks, she approached some people cautiously; happy but still a little cautious. Now after working with her for a month, lots of high value treats around people; she's still polite and calm, but I don't see caution anymore. Could just be the fear period? But our puppy's sire was the same way, he confidently, calmly approached us and has been that way his whole life. Oh, and my last puppy was 12 years ago, we had a rottweiler too. Anyway, his temperment was the same as our current girl. Slightly reserved around strangers but always friendly, sweet and calm.
As far as exercise goes, I'm pretty nervous about hip dysplasia (our rottie had it) so we are taking the slow approach to exercise. Right now, our girl gets a one mile on leash walk (it takes 20 minutes because I let her explore) and we play fetch in the yard, plus she plays TONS with our older dog. I wouldn't do a 2.5 mile walk with my puppy yet, but I'm curious what others will say on that.
Boomer...Akbash/Great Pyrenees Mix (9/2008)